Determination of Lead in Croatian Wines by Graphite Furnace Atomic Absorption Spectrometry

Abstract

Determination of Lead in Croatian Wines by Graphite Furnace Atomic Absorption SpectrometryA method has been developed for direct determination of lead in wine by graphite furnace atomic absorption spectrometry (GFAAS) with Zeeman-effect background correction. The thermal behaviour of Pb during pyrolysis and atomisation stages was investigated without matrix modifier and in the presence of Pd(NO3)2, Pd(NO3)2+ Mg(NO3)2× 6H2O, and NH4H2PO4+ Mg(NO3)2× 6H2O as matrix modifiers. A simple 1:1 dilution of wine samples with Pd(NO3)2as a matrix modifier proved optimal for accurate determination of Pb in wine. Mean recoveries were 106 % for red and 114 % for white wine, and the detection limit was 3 μg L-1. Within-run precision of measurements for red and white wine was 2.1 % and 1.8 %, respectively. The proposed method was applied for analysis of 23 Croatian wines. Median Pb concentrations were 33 μg L-1, range (16 to 49) μg L-1in commercially available wines and 46 μg L-1, range (14 to 559) μg L-1in home-made wines. There were no statistically significant differences (P<0.05) in Pb concentration between commercial and home-made wines or between red and white wines.